This script will retrieve the latest exchange rates from the International Monetary Fund ( based on the US Dollar ), and then updates the currency values in your database to match. If you do a lot of international sales, this is a good way to keep those values current.
This script was written because the others available were either too old or pulled data from unreliable sources.
If your webhost allows access to cron, you have the ability to automate the script to run every few days.